Joseph birdus smith booth and ernest james falconer



(No Model.)

\ J. B. S. BOOTH 85 E. J. FALOONER.

' TELEPHONE.

No. 505,087. Patented Sept. 19, 1893.

F'IG.5.

FIG.4.

fnvenfor's: M

I mama! NITED STATES PATENT Ornicn.

JOSEPH BIRDUS SMITH BOOTH AND ERNEST JAMES FALCONER, OF MANCHESTER,ENGLAND.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 505,087, datedSeptember 19, 1893. Application filed January 31, 1893. Serial No.460,242. (No model.) Patented in England March 2, 1892, No. 4,068-

To all whom it may concern.-

Be it known that we, J OSEPH BIRDUS SMITH Boom and ERNEST JAMEsFALCONER, citi zens of the United Kingdom of Great Britain and Ireland,residing at Manchester, in the county of Lancaster, England, haveinvented certain new and useful Improvements in Telephones, (patented inGreat Britain March 2, 1892, No. 4,068,) of which the following is aspecification. r

This invention relates to electro magnetic telephones of that type orclass in which the poles of a permanent or electro magnet are arrangedon opposite sides of the diaphragm or diaphragms and its object is toincrease the efficiency of such telephones.

According to this invention we arrange a coil upon each pole or polepiece of the mag net or magnets and join them up in the line circuit,preferably in parallel or derivation. Each of the coils is wound orjoined in the same direction. The coils however may in some cases bejoined in series instead of in derivation. In all cases however thecoils are so placed and connected that upon the passage of a currentthey tend to form similar polarity upon the opposite sides of thediaphragm, thus diminishing the magnetic force of the pole piece on oneside of the diaphragm and correspondingly strengthening that on theother. The diaphragm is thus attracted on one side and released on theother upon each variation of current. In the event of an electro-magnetbeing used the energizing coils and the direction of current thereinwill remain constant.

In order that our invention may be more clearly understood, we havehereto appended drawings to which we will refer.

Figure 1 illustrates a cross section of a telephone constructedaccording to this invention with the ear or mouth piece placed over oneof the pole pieces of the magnet. Fig. 2 is a similar section of atelephone with the ear or mouth piece arranged at right angles to theposition in Fig. 1. Figs. 3 and 4E are respectively plans of theinstruments shown in Figs. 1 and 2. Fig. 5 illustrates partly inelevation and partly in section, aview of the instrument represented inFig. 2 at right angles therewith. Figs. 6 and 7 show aform of inconnection with the line circuit. These coils of wire are so wounddisposed and connected that upon the passage through them of an electriccurrent they would tend to create similar poles in each pole piece atthe ends next to the diaphragm. By this means of course the normalmagnetism of one of the pole pieces would be increased and that of r theother diminished. Many methods of winding and joining the coils to givethis result are obvious but a preferred method is to wind both coils inthe same direction and connect them in parallel the beginning of onecoil and the end of the other being connected to one line terminal. Thesame end may of course be easily attained by suitably connecting them inseries.

Between the pole pieces is placed the diaphragm D which is held in placeby and clamped between the two halves E E of the body of the telephone.This telephone body is preferably constructed of ebonite and may besecured to the magnet by the screwsF F. For the purpose of accurateadjustment the pole pieces may be capable of longitudinal movement bymeans of a screw. The diaphragm is thus placed in an intense magneticfield and is attracted equally by both poles until the passage of acurrent through the coils. The diaphragm is then attracted by theincreased magnetism of one pole and the movement is augmented by thecorresponding decrease in the magnetism strength of the pole on theother side of the diaphragm. The pole pieces are preferably notpermanently secured to the limbs of the horseshoe magnet but arefurnished with projections which engage with holes in the magnet. Thelimbs of the magnet are sufficiently elastic to allow of their beingsprung into place over the pole pieces.

In the form shown in Fig. 1 the ear or mouth piece G is placed over onelimb of the magnet and is in communication with one only able recessesformed in the halves E E of the telephone body. The communication may beeffected by carrying a passage or hole J through the magnet limb andpole piece. Both of the chambers may if desired be in communication withthe ear piece, it being preferred in this case to form the ear piece Gon one side of the telephone body as shown in Figs. 2, 4, and 5,suitable holes leading to each of the chambers.

Figs. 6 and 7 illustrate a form which may be employed when it is desiredto use the same instrument both as a transmitter and as a receiver. Theinstrument is provided with a lateral ear piece as shown in Figs. 2, 4and 5, which however is in communication with one side only of thediaphragm- The chamber onthe other side of the diaphragm is incommunication with a peculiar quadrant shaped mouth or trumpet K theentrance of which comes about opposite to the speakers mouth when theear piece is placed to the ear. The pole pieces and coils on each sideof the diaphragm may if desired in large instruments be multiplied andjoined and connected in a manner similar to that employed with thesingle pair of coils.

Having now particularly described and ascertained the nature of our saidinvention and in what manner the same is to be performed, we declarethat what we claim is- 1. In an electric telephone, a single diaphragmarranged perpendicular to and between two co-axial pole pieces ofapermanent or electro-magnet, the pole pieces having thereon coilsincluded in the line circuit and wound or joined in such a manner thatthe line current tends to produce similar polarity in the ends of thepole pieces next to the diaphragm, substantially as set forth.

2. In a telephonic apparatus, a diaphragm having an air'chamber on eachside, a receiving and a transmitting aperture entering said JOSEPHBIRDUS- SMITH BOOTH. ERNEST JAMES FALOONER.

Witnesses:

GEORGE WILLIAM ROWE ARTHUR WILLIAM PULMAN.

